Any tips for MX1 HSC? (1 Viewer)

lyounamu

Reborn
Joined
Oct 28, 2007
Messages
9,998
Gender
Male
HSC
N/A
Let's share some tips! I think it will be great to share some good points to help ourselves, don't you think?

I do have limited knowledge but I might really have some knowledge that people may not be aware and so do you!

I will start first:

When you integrate, you can actually flip the terminals by introducing minus like this:

- I(1 -> 5) = I(5 -> 1)

This may be a pretty damn poor tip but I had to come up with something. And this is not totally useless...so please share!

EDIT: Thought of another tip:

when you have 0 gradient, that means that the line will just be a straight line. I have noticed this in few HSC papers where they told us to find a gradient and the gradient turned out to be 0. And they also asked me to draw a graph. All you need to do in that case is to substitute random number into the calculator in the given domain and just draw a straight line! easy 2 marks, given to you! Come on guys~
 
Last edited:

midifile

Na Na Na Na Naa
Joined
Oct 11, 2006
Messages
1,143
Location
Sydney
Gender
Female
HSC
2008
For any tricky binomial theorum questions, start by expanding (1 + x)n

Then if you still cant work out what to do try integrating it and differenting it (but if you integrate make sure you dont forget about the C)
 

kaz1

et tu
Joined
Mar 6, 2007
Messages
6,960
Location
Vespucci Beach
Gender
Undisclosed
HSC
2009
Uni Grad
2018
Try learning polynomial division by inspection. It's much quicker than long division.
 

lyounamu

Reborn
Joined
Oct 28, 2007
Messages
9,998
Gender
Male
HSC
N/A
kaz1 said:
Try learning polynomial division by inspection. It's much quicker than long division.

What is that? Excuse my lack of knowledge (or my lack of understanding of complex mathemtical terminology).
 

cutemouse

Account Closed
Joined
Apr 23, 2007
Messages
2,250
Gender
Undisclosed
HSC
N/A
Yeah our teacher taught us Polynomial division by inspection. It's much faster, but it only works when there aren't too many terms, and when there's one factor. Well, it's always possible, but it gets tricky.
 

lyounamu

Reborn
Joined
Oct 28, 2007
Messages
9,998
Gender
Male
HSC
N/A
jm01 said:
Yeah our teacher taught us Polynomial division by inspection. It's much faster, but it only works when there aren't too many terms, and when there's one factor. Well, it's always possible, but it gets tricky.
But what is it? How do you use it?

Thanks for the help.
 

harryboyles

Member
Joined
Sep 13, 2007
Messages
36
Gender
Male
HSC
2008
For questions which require you to answer using an exact value, you can evaluate it on your calculator... as long as you know how to convert back to exact value. For example, if I get 5.026548246 as an answer, I can divide by pi on the calculator to get 8/5. To reverse that, we multiply by pi, but we don't do it on our calculator. Instead, we do it symbolically on our writing paper. The answer would be written as 8pi/5.

The same thing can be done with other common values:
0.866025... > 3^0.5 / 2
0.707107... > 1 / 2^0.5
1.732050... > 3^0.5
0.577350... > 1 / 3^0.5

This can help immensely if you're prone to making careless algebraic mistakes (like I am).
 

cutemouse

Account Closed
Joined
Apr 23, 2007
Messages
2,250
Gender
Undisclosed
HSC
N/A
It is what it says it is: Division of Polynomials by Inspection.

Hard to explain but, if the factor is (x+1), and the term you need to divide it through is x3+x2+1 (dunno if it'll divide perfectly, just an example), then you just do something like: (x+1)(x2+__x+___) and try and fill in the gaps.

That's pretty much it, but yeah hard to explain in writing.
 

bored of sc

Active Member
Joined
Nov 10, 2007
Messages
2,314
Gender
Male
HSC
2009
If you're really stuck write down something in relation to the question i.e. formulae, expressions etc. It might help you pick up a mark or two.
 

kaz1

et tu
Joined
Mar 6, 2007
Messages
6,960
Location
Vespucci Beach
Gender
Undisclosed
HSC
2009
Uni Grad
2018
lyounamu said:
But what is it? How do you use it?

Thanks for the help.
(x2-6x+5)/(x-5) = (x-5)(x -1)

First you ask yourself what do you multiply with x to get x2?
It is x so you put x as the first term.


Since -5 multiplied by x is -5x you have -5x's but you need -6x so you put negative 1 as the next term.
 

vds700

Member
Joined
Nov 9, 2007
Messages
861
Location
Sydney
Gender
Male
HSC
2008
-Make sure your calculator is in the right mode (rad or deg)
-Draw diagrams to help u answer questions
-When doing inegration by substituition, remember to change the limits
 

friction

Member
Joined
May 8, 2006
Messages
494
Gender
Male
HSC
2008
Its really hard to think up tips on the spot but in my past papers if i do any i will tell you.

Oh i dont know if ext 1 needs it. But to intergrate sec x times top and bottom buy sec x + tan x like this
sec x

sec ^2 x + sec xtan x / (sec x + tan x)

the intergral of that is ln (sec x + tan x)
 

lyounamu

Reborn
Joined
Oct 28, 2007
Messages
9,998
Gender
Male
HSC
N/A
This is really good stuff guys. Keep them coming!!! I reckon everyone will beneift from this great activity~~~
 

friction

Member
Joined
May 8, 2006
Messages
494
Gender
Male
HSC
2008
kaz1 said:
(x2-6x+5)/(x-5) = (x-5)(x -1)

First you ask yourself what do you multiply with x to get x2?
It is x so you put x as the first term.


Since -5 multiplied by x is -5x you have -5x's but you need -6x so you put negative 1 as the next term.
Im pretty sure i could do long devision just as quick. Thats all you do in long devision anyway. For ones with only x2s as the biggest term you can usually just figure them out by looking at it or use the -b + or - square root of (b^2 -4ac) thingy, btw that can be used in lots of places

Also (a-b) ^2 > 0 for all values of a and b
And (a + b) ^ 2 = (a-b)^2 + 4ab

These can be used in many places that the other just normal expansion of it. more 4U stuff but but i use it everywhere and i really dont know what is 3u and what is 4u.
 
Last edited:

friction

Member
Joined
May 8, 2006
Messages
494
Gender
Male
HSC
2008
When doing a induction you practically always have to use what you assume true for k in you answer.
 

friction

Member
Joined
May 8, 2006
Messages
494
Gender
Male
HSC
2008
Dont rush but dont go to slow be calm and you will get a better mark less silly mistakes all that worrying does is make ur mark worse. Know ur rules needed in 2u like trapaziodal etc. Circle geometry the 2 most common are cyclic quads and angles on the same arc. Also angle to a tangent is pretty common. You can prove similarity by sides in ratio so if you know 1 side is equal to another you will often have to use it somewhere i often forget to use sides in ratio.

Cant think
 

adnan91

Member
Joined
Mar 29, 2008
Messages
347
Location
Disney Land
Gender
Male
HSC
2008
friction said:
Its really hard to think up tips on the spot but in my past papers if i do any i will tell you.

Oh i dont know if ext 1 needs it. But to intergrate sec x times top and bottom buy sec x + tan x like this
sec x

sec ^2 x + sec xtan x / (sec x + tan x)

the intergral of that is ln (sec x + tan x)
thats 4u
 

friction

Member
Joined
May 8, 2006
Messages
494
Gender
Male
HSC
2008
Probably all my hints are 4u. 3u doesnt really need and tips or tricks to get past bits often.
 

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Top